1. Field of the Invention
This invention relates to a foreign matter and defect detecting apparatus for detecting minute foreign matters and/or defects existing on a semiconductor substrate etc. with high sensitivity and high speed.
2. Description of the Related Art
In production lines of semiconductor substrates, thin film substrates, etc., in order to maintain and improve product yield, there is widely carried out inspection of defects and foreign matters existing on surfaces of semiconductor substrates, thin film substrates, etc. For example, with a sample of a semiconductor substrate etc. before formation of a circuit pattern, it is necessary to detect minute defects and foreign matters (herein after referred to as defects) of a size of 0.05 μm or less on the surface. In the conventional inspecting apparatus, in order to detect such defects, a laser beam of visible light converged to a diameter of a few tens of μm is applied onto the sample surface, and scattered light from the defects are collected and detected. Moreover, with a sample of a semiconductor substrate etc. after circuit pattern formation, the defects are recognized by irradiating a collimated laser beam on the sample surface, collecting the scattered light generated on the sample surface, while diffracted light from a periodical pattern is shaded with a spatial filter, scattered light from the non-periodical pattern and defects is detected, and signals resulting from the non-periodical pattern is eliminated by die comparison.
As an inspecting apparatus that uses UV light having a shorter wavelength than the visible light as a light source, JP 2003-130808 A discloses a method for irradiating a sample using a UV pulsed laser as a light source with a reduced peak of the pulse and an apparatus therefor.